[SYCL][NFC] Remove boost header includes from cmake (#19051)

Boost header usage was removed in
#18599

Author: sergey-semenov

sycl/source/CMakeLists.txt

@@ -61,7 +61,6 @@ function(add_sycl_rt_library LIB_NAME LIB_OBJ_NAME)
     PRIVATE
       ${CMAKE_CURRENT_SOURCE_DIR}
       ${sycl_inc_dir}
-      ${BOOST_UNORDERED_INCLUDE_DIRS}
   )
 
   # Object libraries are not linked, so these "libraries" are in fact include

sycl/test/CMakeLists.txt

@@ -16,7 +16,6 @@ set(SYCL_THREADS_LIB ${CMAKE_THREAD_LIBS_INIT})
 # TEST_INCLUDE_PATH is used for syntax-only verification of type information.
 list(APPEND test_includes ${SYCL_INCLUDE})
 list(APPEND test_includes ${SYCL_SOURCE_DIR}/source)
-list(APPEND test_includes ${BOOST_UNORDERED_INCLUDE_DIRS})
 if(SYCL_ENABLE_EXTENSION_JIT)
   list(APPEND test_includes ${LLVM_EXTERNAL_SYCL_JIT_SOURCE_DIR}/jit-compiler/include)
   list(APPEND test_includes ${LLVM_EXTERNAL_SYCL_JIT_SOURCE_DIR}/common/include)

sycl/unittests/CMakeLists.txt

@@ -1,6 +1,5 @@
 add_custom_target(SYCLUnitTests)
 set_target_properties(SYCLUnitTests PROPERTIES FOLDER "SYCL tests")
-include_directories(${BOOST_UNORDERED_INCLUDE_DIRS})
 
 foreach(flag_var
     CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE